A vehicle internal-combustion engine has fuel injection valves and a delivery pipe. The fuel injection valves are provided for respective cylinders. The fuel delivery pipe delivers fuel to each of the fuel injection valves. The fuel delivery pipe is made by aluminium die-casting.
However, because the fuel delivery pipe has a lower mechanical strength, a fuel delivery pipe having a higher mechanical strength has been required. Besides, it has been reported that high level of alcohol containing fuel reacts directly with (or causes dry corrosion on) aluminium. Furthermore, it has been shown that gasohol also can cause dry corrosion. Because of this, the inner surface of the fuel delivery pipe needs to be plated with alcohol-corrosion resistant material. However, plating aluminium needs zinc immersion as the pretreatment.
Thus, there is a need for a fuel delivery pipe that has a higher mechanical strength and needs no pretreatment for plating.